A Need for Universal Audio Terminologies and Improved Knowledge Transfer to the Consumer

Transcription

1 A Need for Universal Audio Terminologies and Improved Knowledge Transfer to the Consumer Rob Toulson Anglia Ruskin University, Cambridge Conference 8-10 September 2006 Edinburgh University

2 Summary Three discussion topics Each are a particular area of research, but all are interlinked The effect of modern listening trends on the techniques employed for music production and final mastering The impact of MP3 audio on production methods Reproduction quality and random play High-level production technologies for the listener; allowing a little of the studio into the home Educating the listener Software and hardware Moving towards a universal language of audio terminologies Scientific representations of audio terms Sharing the language of audio production with the consumer

3 The effect of modern listening trends on the techniques employed for music production and final mastering Historically the production and mastering of a record has been targeted at a particular media or outlet Analogue (vinyl, cassette tape) Digital media formats (16-bit 44.1kHz CD, 24-bit DVDA) Radio MPEG1 Layer 3 (MP3) and compressed audio Unlike HD television broadcast, digital technology has been used to reduce the quality of reproduced music and audio! MP3 compression utilises the fact that our ears can only respond at a finite speed to changes in sound pressure so some of the data can be removed from high resolution audio and we won t be able to tell the difference! 16-bit 44.1kHz CD quality equates to kbps, MP3 is usually compressed to 128kbps Unfortunately it doesn t take much ear training to hear the major differences in quality between MP3 and uncompressed audio.

4 The effect of modern listening trends on the techniques employed for music production and final mastering Modern listening trends rely heavily on MP3 compressed audio Music consumers seem to be most interested in system functionality and convenience - quantity above quality. MP3 audio allows users to play songs in random order from a vast database of songs. Songs from different releases are rarely have the same output characteristics. The mastering process is designed for arranging song orders and aligning relative output levels. The use of MP3s goes totally against the principle of improving audio quality and mastering an artistic record. Listeners musical preferences could become more based on the reproduction system used as apposed to the quality and integrity of the music being listened to. How do we approach this issue? Accept the current trends and develop production and mastering methods specifically designed for MP3 audio. Educate the music buying public in the values of audio and musical sound quality.

5 High-level production technologies for the listener; allowing a little of the studio into the home Consumers of music are rarely educated in production techniques and the concepts of audio quality. For example, equaliser systems in home audio devices It is suggested that a more valuable system would be to allow consumers to improve their home hi-fi audio by, for example increasing the warmth or reducing sibilance in a track or attenuating problem standing waves for a given system in a particular room If only the consumer understood what these terms meant! Further opportunities for high-level advanced home audio processing Intelligent EQ for correction of room acoustics Normalising outputs for CD duke boxes Intelligent output level control for random MP3 playback Intelligent random song selection Intelligent automated DJ (beat and pitch) mixing Advanced correction/optimisation for automotive vehicle cabins

6 Moving towards a universal language of audio terminologies Categorising audio terminologies Rumsey s (2005) chart of sound quality terminologies Technical descriptors can, by definition, be quantified scientifically Pitch, spectral balance - guitar string example Compression Noise Spatial descriptors are usually quite easy to quantify scientifically Wide Up-front Boxy Timbral descriptors are rarely defined by specific scientific parameters - though this has been shown to be possible (Disley et al, 2006), (Johnson & Gounaropoulos, 2006). Warm Harsh Bright

7 Describing timbre Moving towards a universal language of audio terminologies Timbre is that attribute of auditory sensation in terms of which a listener can judge two sounds simultaneously presented and having the same loudness and pitch as being dissimilar (ANSI, 1960) Timbre terminology often uses imagery relating to emotions and senses This is metaphoric by nature and hence subjective The use of subjective imagery to describe scientific parameters is quite paradoxical Examples Warm Touch Bright Sight Sweet Taste Smell? Putting scientific parameters to timbre descriptors Katz (2002) spectral chart of subjective terms

8 Describing timbre Moving towards a universal language of audio terminologies But timbre descriptors often describe a combination of scientific and spatial qualities, for example warmth Energy in the lower mid-range of the audio spectrum ( Hz) Depletion in the upper mid-range of the audio spectrum (2.5 6 khz) Subtle non-linear compression as in analogue audio recording devices (analogue tape) Subtle harmonic distortion as in analogue (thermionic valve) audio amplification devices So if the above describes warmth, does that mean the opposite describes cold? Atsushi and Martins (2005) experimented with several bipolar timbral adjectives Dark Bright Thick Thin Muddy Clear Strong Weak

9 Moving towards a universal language of audio terminologies Visualising musical sound Bright sounds have Greater energy in the high-midrange and treble regions (2-20 khz) and/or Depletion in the bass and lower midrange ( Hz). A particularly bright percussive instrument is the cymbal, but many timbral descriptors for instruments are often contradictory and confusing, for example Zildjian Dark Thin Crash Byzance Medium Thin Crash Medium Thin Crash - Significant, washy and fairly dark sound with a full frequency spectrum. Voluminous attack with moderate sustain ( 2006)

10 Moving towards a universal language of audio terminologies Visualising musical sound Colour is often used as a timbre descriptor for individual instruments Trumpet example Flute example Cello example Colour descriptors often group together a number of metaphoric descriptors, which in turn relate back to scientific parameters, for example - Trumpet - scarlet indicates warm, smooth, bold - Cello - brown indicates rich, deep, thick So the use of metaphors and imagery is a very powerful tool for describing complex attributes of music and audio in a single term. Unfortunately, the subjective nature of the current use of these terminologies allows for regular contradiction and confusion.

11 Conclusions Modern consumer listening trends embrace the use of MP3 compressed audio, though generally at the expense of the reproduced audio quality. There is a need to educate listeners in the values of quality audio which in turn can provide a business case for more intelligent home audio processing hardware and software systems. Given that many timbral adjectives are subjective by nature, music production industry professions must first develop a uniform language of terminologies before advanced knowledge can be transferred to consumers. It has been shown here and previously that it is possible to define particular scientific qualities of audio which can be referenced using simple metaphoric terms or timbral adjectives. Groups of terms can further be used to describe complex sounds as higher-level adjectives. Further psychoacoustic experimentation correlating timbral adjectives with specific scientific properties should be conducted to achieve a universal language of music and audio descriptors.

12 References and Information Sources Atsushi, M. & Martens, W. L. (2005). Timbre of Nonlinear Distortion Effects: Perceptual Attributes Beyond Sharpness? Proceedings of the Conference of Interdisciplinary Musicology, Montreal, Canada. Disley, A. C., Howard, D. M. & Hunt, A. D. (2006). Spectral correlation of timbral adjectives used by musicians, The Journal of the Acoustical Society of America, 119(5), p3333. Hood, J. L. (1997). Valve and Transistor Amplifiers, Oxford, Newnes Publishing. Hood, J. L. (1999). Audio Electronics, Oxford, Newnes Publishing. Howard, D. M. & Angus, J. (2006). Acoustics and Psychoacoustics, 3rd Edition, Oxford, Focal Press. Howard, D. M. & Tyrrell, A. M. (1997). Psychoacoustically informed spectrography and timbre, Organised Sound (1997), 2: Cambridge University Press. Johnson, C. G. & Gounaropoulos, A. (2006). Timbre interfaces using adjectives and adverbs, Proceedings of the 2006 International Conference on New Interfaces for Musical Expression, Paris, France. Katz, B. (2002). Mastering Audio, Focal Press. Owen, O. (Editor) (2006). Tech Angst, Future Music, Future Publishing Ltd, p13. Rumsey, F. & McCormick, T. (2006). Sound and Recording, 5th Edition, Oxford, Focal Press. Rumsey, F. (2005). Psychoacoustics of Sound Quality, Proceedings of the Art of Record Production Conference, London, Scholes, P. A. (1970). The Oxford Companion to Music, London, Oxford University Press. White, P. (2002). Creative Recording part one, effects and processors, 2nd Edition, London, Sanctuary. (2006). accessed September 2006.

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